SURGICAL INSTRUMENT AND STEERING GEAR FOR IT

Description

[0001] The invention relates to a surgical instrument and a steering gear therefor.

[0002] Surgical instruments are known from the prior art that can be guided manually or by a robot. These instruments feature a tool tip that can be pivoted using several interlocking pivoting links. These pivoting links are connected to a multitude of steering wires or cables to achieve sensitive control of the tool tip. Using many thin steering wires compared to a few thicker ones allows for a more even distribution of force in all deflection directions.

[0003] A generic surgical instrument is known, for example, from US 5 454 827, in which the distal-side pivoting members are coupled via four steering wires to a spatially adjustable swash plate arranged on the proximal side in such a way that a movement of the spatially adjustable swash plate causes a corresponding relative movement of the distal-side pivoting members and thus a pivoting of the tool tip, wherein the movement of the spatially adjustable swash plate is carried out manually via a type of joystick which is directly coupled to it.

[0004] The design of the drive for the steering wires with the spatially adjustable swash plate, on which all four steering wires are mounted, has the advantage that this enables a spatially compact design and only one component has to be moved in order to be able to address all steering wires.

[0005] The disadvantage of this known construction is the use of only a small number of steering wires, namely only four, and furthermore the exclusively manual operation of the spatially adjustable disc serving as the drive for the steering wires, which makes a sensitive and reproducible adjustment of the distal swivel members hardly possible.

[0006] US Pat. No. 7,699,855 discloses a surgical instrument with an interface for connecting the instrument to a robotic arm. All drives controlling the instrument are located within the robotic arm. The rotation angles are transmitted from the drives to the instrument via coupling discs in a common separation plane.

[0007] WO 2014 / 004 242 also describes such an interface, with the drives being installed in the robot arm.

[0008] The above design is associated with a complex structure and an indirect control system subject to play. The drives are not directly located within the surgical instrument, resulting in a nonlinear transmission behavior when controlling the swash plate, which is difficult to replicate in a software control system.

[0009] US 10,105,128 B2 also discloses a control of such a tool tip; there, this is done via a mechanism that includes toothed disk segments and articulated rods to transmit the movement of the drives to the swash plate.

[0010] Furthermore, DE 10 2019 121092 A1 discloses a steering gear with a swashplate and two motors that move the swashplate. In particular, DE 10 2019 121092 A1 discloses the preamble of claim 1.

[0011] Based on this prior art, it is the object of the present invention to provide an improved steering gear for a surgical instrument, which has a drive of the spatially adjustable swash plate with linear transmission behavior and is designed in a space-saving manner.

[0012] This object is achieved by a steering gear having the features of claim 1. The further object of providing a surgical instrument whose spatially adjustable swash plate is driven by a structurally simple and space-saving steering gear is achieved by the surgical instrument having the features of dependent claim 7.

[0013] Further developments and preferred embodiments of the steering gear and the surgical instrument are set out in the subclaims.

[0014] A first embodiment of the steering gear according to the invention for a surgical instrument has two motorized drives. It is designed to spatially align a swash plate via the setting angles of the two drives, which swash plate is designed to control a distal angling mechanism of the surgical instrument. According to the invention, a first of the two drives has a first motor that drives a worm shaft that drives a worm gear ring of a double gear consisting of the worm gear ring and a bevel gear ring. A second of the two drives has a second motor that drives a worm shaft that drives a worm gear ring of a double gear consisting of the worm gear ring and a bevel gear ring. The swash plate is arranged between the two bevel gear rings, which face each other and lie on a common axis A.

[0015] The two worm shafts arranged tangentially on the worm gear rims of the double gears serve to transmit the rotary motion of the respective motor by 90° to the respective double gear, thus moving the swashplate gear, to which the bevel gear rims of the double gears belong. Advantageously, the steering gear according to the invention with the worm shafts offers a linear transmission behavior of the drive force to the swashplate, in that the worm gears are connected as double gears to a respective bevel gear of the gear. Advantageously, the steering gear according to the invention allows all four drive axes of the surgical instrument to be freely selected for control. The design of a software control system is thus easier to implement.Depending on the spindle pitch and the number of spindle threads, a worm gear can be designed to be self-locking, especially since friction in a worm gear is generally higher than in other types of gears. Using a worm gear with a self-locking mechanism, which is easily achieved for this type of gear, can ensure precise movement of the tool tip and eliminate the need for an additional braking device.

[0016] Due to the arrangement of the motors offset by 90° to the common axis of the bevel gear rims, horizontal installation space in the direction of the common axis A of the bevel gear rims is saved with regard to the alignment of the swash plate.

[0017] The drive axis of the second motor can be positioned in any orientation in a plane parallel to the axis of the first motor. For example, the drive axes of the worm shafts arranged tangentially to the respective dual gears can be rotated by an angle, e.g., 30°, 45°, or 90°, if this is advantageous or necessary in the respective installation context.

[0018] In a preferred embodiment of the steering gear according to the invention, a drive axis C of the first motor can be parallel to a drive axis C' of the second motor. A so-called axially parallel arrangement of the motors enables a compact and thus advantageously space-saving arrangement of the steering gear components. Alternatively, depending on the design requirements of the surgical instrument or a connection to a robot arm, non-axially parallel arrangements of the motors can also be realized. The two motors can be arranged freely and independently of each other on the double gears in terms of their positioning, as long as the respective worm shaft engages precisely with the respective worm gear ring.

[0019] In a further embodiment of the steering gear according to the invention, the swash plate can be coupled to a third gear. The third gear, as part of the swash plate gear, meshes with the two bevel gear rings of the two double wheels. The axis of rotation D of the third gear is at a right angle to the common axis A of the driven double wheels. Advantageously, the three meshing gears transmit every movement of the two driven gears directly to the third gear coupled to the spatially adjustable swash plate, so that the actuating movements of the drives are transmitted via the swash plate, which can then be tilted or pivoted about the common axis A and axis of rotation D.

[0020] Furthermore, in a further embodiment of the steering gear according to the invention, the swash plate can be coupled to a fourth gear, which is coupled to the two bevel gear rings of the two dual gears and is arranged on the opposite side of the third gear. This completes the rotating gear chain and ensures a uniform, backlash-free power distribution.

[0021] In yet another embodiment of the steering gear according to the invention, the worm shaft is a multi-start worm shaft. This results in a faster angling of the tool tip of the controlled surgical instrument and less self-locking compared to a single worm shaft at the same drive speed. To achieve a corresponding angling speed with a single worm shaft, the motor speed can be increased accordingly or a motor with a correspondingly higher speed can be used.

[0022] Preferably, the double gear is a one-piece double gear. Alternatively, each double gear can consist of a bevel gear and a worm gear connected to each other. The combination of the worm gear ring and the bevel gear ring achieves a direct transmission of the movement initiated by the drive to the respective gears of the swashplate gear.

[0023] The movement of the worm shaft is directly transferred to the two gears, each of which meshes with the bevel gear ring of the double wheel.

[0024] The invention further relates to a surgical instrument comprising a shaft, an actuating unit arranged at the proximal end of the shaft, and a tool arranged at the distal end of the shaft. The tool has a tool tip that can be angled by means of a distal angling mechanism. The angling mechanism can be controlled or aligned by a swash plate that can be spatially aligned by means of two drives, for which purpose the surgical instrument comprises a steering gear according to the invention. The two drives are part of the steering gear according to the invention, which is designed to transmit the setting angles of the two drives to the spatial alignment of the swash plate in order to thus control the angling mechanism.

[0025] The steering gear according to the invention allows the surgical instrument to be constructed in a simple and space-saving manner, enabling easy connection to a robotic arm, with the movement of the drives being transmitted linearly to the tool tip. This results in precisely controllable use of the surgical instrument.

[0026] In order to be able to adjust the spatially adjustable swash plate three-dimensionally despite the rotationally fixed coupling with the third gear, which engages with the two bevel gear rings of the two double wheels, i.e. to be able to superimpose the tilting or pivoting movements with a rotation of the swash plate around the longitudinal axis, a preferred embodiment of the surgical instrument can provide that the swash plate is mounted so as to be rotatable about the longitudinal axis B of the shaft via a bearing ring in a steering ring which is rotationally fixedly coupled to the third gear. For the rotational coupling of the swash plate to a main shaft running coaxially to a longitudinal axis B of the shaft, the swash plate can be gimbal-coupled to the main shaft. Thus, the tool tip can be rotated around the longitudinal axis of the shaft by means of the swash plate in addition to the pivoting or tilting by the two drives by the main shaft relative to the longitudinal axis of the shaft.

[0027] To implement the gimbal mounting of the spatially adjustable swash plate, an embodiment of the surgical instrument according to the invention can provide that the swash plate is pivotably mounted on a universal joint disc via two bearing pins arranged 180° apart, which in turn is pivotably mounted on the main shaft via two bearing pins arranged 180° apart. The bearing pins of the swash plate and the universal joint disc are arranged 90° apart. The gimbal mounting enables movement in all three spatial axes, allowing the tool tip to be precisely controlled.As an alternative to a universal joint with two pairs of pins crossed at right angles for the cardanic mounting of the swash plate on the main shaft, an advantageous embodiment can provide that the main shaft has two guide grooves in its outer surface, which extend diametrically and along the main shaft, for the cardanic mounting. The swash plate, which is circular in shape with an outer side and an inner side, has two pins arranged diametrically and radially inwardly on the swash plate. Each of the two pins, which are firmly mounted on or in the swash plate, engages in one of the guide grooves formed on both sides of the main shaft, so that a rotation angle of the shaft can be transmitted to the swash plate.This advantageously results in a torsionally rigid connection between the main shaft and the swashplate, which allows for rotational angle transmission even with a large angular misalignment (± 40° and more) and axial misalignment. It is also very compact in design and easy to manufacture and assemble. However, a curved-tooth coupling can also be used for the gimbal mounting of a swashplate on a main shaft, despite a relatively small angular misalignment, a constant velocity joint despite its complex manufacturing and assembly requirements, or a material-to-material coupling, which is often associated with a rotational angle transmission subject to backlash.

[0028] In a further embodiment of the surgical instrument according to the invention, steering wires extend in the longitudinal direction of the shaft and are connected to the swashplate of the steering gear. Preferably, the steering wires can be releasably attached to the swashplate, for example, by means of a clamp connection, so that in the event of damage, the steering wires can be easily replaced. Since the swashplate is rotationally coupled to the main shaft and is rotatably mounted by the bearing ring in the steering ring, which is rotationally fixedly coupled to the third gear, twisting of the steering wires is prevented, which is further advantageous for pivoting the tool tip relative to the longitudinal axis and rotating it about the longitudinal axis of the shaft.

[0029] Furthermore, a further embodiment of the surgical instrument according to the invention provides that the fourth gear is coupled to the swash plate via a bearing ring with the steering ring, whereby the fourth gear is freely rotatable relative to the third gear. This fourth gear completes the rotating toothed chain and thus ensures a uniform, backlash-free force distribution.

[0030] In a further embodiment of the surgical instrument according to the invention, an actuating element is mounted axially displaceably in the shaft and is operatively connected to the actuating unit on the proximal side. The distal deflection mechanism of the deflectable tool tip consists of pivoting members arranged at the distal end of the shaft, which are connected to the swashplate of the steering gear via the steering wires running in the longitudinal direction of the shaft. The steering wires can preferably be releasably clamped to the swashplate by means of a clamp connection, so that the steering wires can be easily replaced in the event of damage. Alternatively, the steering wires can also be attached to the swashplate, for example, by welding or crimping.

[0031] In a further embodiment of the surgical instrument according to the invention, the radial distance of the steering wires from the longitudinal axis of the shaft is greater at the swash plate than at the proximal end of the shaft from which the steering wires emerge. The steering wires can extend from the proximal end of the shaft directly to the swash plate, with the steering wires running at an angle to the swash plate other than 90°. Alternatively, a fan-disk disk can be arranged on the main shaft distally in front of the swash plate, which increases the radial distance of the steering wires emerging from the proximal shaft end from the longitudinal axis of the shaft, so that the steering wires run approximately parallel to one another between the fan-disk disk and the swash plate and form an angle of approximately 90° with respect to a disk surface of the swash plate. Due to the smaller installation space requirement, the variant without a fan-disk disk may be preferred.By increasing the radial distance of the steering wires from the longitudinal axis of the shaft, for example from a diameter of 4 mm to a diameter of 18 mm, not only is the assembly and manufacture of the drive of the steering wires equipped with the spatially adjustable disc simplified, but also the adjustment angle of the spatially adjustable disc or, as a result of the enlarged lever, the forces required for bending are reduced in order to achieve a pivoting angle of the tool tip that corresponds to the extent of the diameter increase.

[0032] In order to avoid a collision of the gears with the steering wires and possibly the actuating element when pivoting the third and fourth gears relative to the longitudinal axis of the shaft, recesses for the steering wires and the actuating element can be formed in the gear rims of the third gear and the fourth gear.

[0033] The surgical instrument according to the invention has the advantage that many thin steering wires can be used to control the pivotable tool tip and that this control is sensitive, precise and reproducible due to the motorized drive for the spatially adjustable disc on which the steering wires are mounted on the proximal side.

[0034] Further embodiments of the steering gear and the surgical instrument, as well as some of the advantages associated with these and other embodiments, will become clear and easier to understand from the following detailed description with reference to the accompanying figures. Objects or parts thereof that are substantially the same or similar may be provided with the same reference numerals. The figures are merely a schematic representation of an embodiment of the invention. The drawings illustrate an exemplary embodiment of the invention. The drawings and description contain numerous features in combination. Those skilled in the art will expediently consider the features individually and combine them into useful further combinations while adhering to the scope of the claims.

[0035] Showing: Fig. 1 is a perspective view of the surgical instrument with a schematically illustrated actuating unit, Fig. 2 is a perspective detailed view of a first embodiment of the steering gear according to the invention, Fig. 3 is a perspective detailed view of a further embodiment of the steering gear, and Fig. 4 is a perspective, partially cut-out detailed view of the swash plate gear, Fig. 5 is a perspective, partially cut-out view of a steering gear according to a further embodiment.

[0036] In Fig. 1 1 shows a surgical instrument 1 with a hollow shaft 2, which has an actuating unit 4 arranged at the proximal end 3 of the shaft 2 and a tool tip 6 arranged at the distal end 5 of the shaft 2. The tool tip 6 is connected to an instrument 7, wherein the instrument 7 can be actuated via an actuating element 8 mounted axially displaceably in the shaft 2, which is operatively connected to the actuating unit 4 on the proximal side. The actuating unit 4 can be a manually operable handle or a structural unit designed for robotic use, i.e., one that can also be actuated without manual intervention.

[0037] The instrument 7 of the tool tip 6 can, for example, be a tool provided with jaw parts, as in Fig. 1 shown, or it could be an endoscope, an applicator or the like.

[0038] The tool tip 6 can be pivoted relative to the longitudinal axis B of the shaft 2 via a joint mechanism 9, wherein the joint mechanism 9 consists of pivoting members 11 arranged at the distal end of the shaft 5, which are connected via steering wires 12 running in the longitudinal direction of the shaft 2 to a drive 13 arranged at the proximal end 3 of the shaft 2 such that a movement of the proximal-side drive 13 causes a corresponding relative movement of the distal-side pivoting members 11 and thus a pivoting of the tool tip 6.

[0039] Even if only the term steering wires 12 is used above and below, steering cables can also be used functionally, which is why the term steering wires 12 should also be read and understood as a synonym for steering cable.

[0040] The actuating element 8, which is mounted axially displaceably in the shaft 2 and is used to actuate the instrument 7, which consists for example of two jaw parts, is designed as a pull / push rod in the embodiments shown.

[0041] The drive 13 for the steering wires 12 is designed as a motorized drive 13 in the surgical instrument 1 shown in the figures and described below.

[0042] The core of the drive 13 is a spatially adjustable swash plate 14 ( Fig. 2 bis 5 ), on which the steering wires 12 are mounted such that a displacement of the swash plate 14 via the steering wires 12 mounted on it causes a pivoting of the tool tip 6. The swash plate 14 can be displaced by means of the motorized drive 13.

[0043] By using a motorized drive 13 for the swash plate 14, it is possible to precisely, sensitively, and reproducibly control the steering wires 12 for pivoting the distal pivoting elements 11 or the tool tip 6. Furthermore, the number of steering wires 12 to be used is irrelevant for a motorized steering gear 13.

[0044] In Fig. 2 and 3 The steering gear 13 is shown in a simplified manner, with the steering gear 13 having the swash plate 14 in the middle. Four gears are connected to the swash plate 14, which form an arrangement diametrically opposite to the swash plate 14. Below and above the swash plate 14 in Fig. 2 A third gear 25 and a fourth gear 31 are arranged and operatively coupled to the swash plate 14. This means that a movement of one of these gears 25, 31 results in a direct movement of the swash plate 14. Double gears 18, 18' arranged on the left and right sides, respectively, mesh with the gears 25, 31. For this purpose, the double gears have bevel gear rings 15, 15', which mesh directly with the gear rings of the gears 25, 31. The double gears 18, 18' have worm gear rings 19, 19' on sides facing away from one another along their central axis A, which also forms the common axis of rotation of both double gears 18, 18'. A worm shaft 16, 16' meshes with each of these worm gear rings 19, 19'. These worm shafts 16, 16' extend at a 90° angle to the rotational axis A and can either be at a 90° angle to a longitudinal axis of the instrument B or parallel to it. The latter is in Fig. 3 shown, with a rotational axis of the worm shafts 16, 16' (rotational axis C and C') running parallel to the longitudinal axis of the instrument B. The worm gears 16, 16' are driven by motors 17, 17'. The rotational axis C, C' of the worm gears 16, 16' is the same as the rotational axis of the motors 17, 17'. Fig. 2 these axes of rotation C, C' are perpendicular, ie at right angles, to the common axis A and perpendicular to the longitudinal axis B and thus, in the illustrated neutral position of the swash plate 14, also parallel to a rotation axis D of the third gear 25 and the fourth gear 31.

[0045] Of course, arrangements of the motors 17, 17' and the worm shafts 16, 16' that deviate from the examples shown are also conceivable. The arrangement of the drive units consisting of motor and worm shaft can be freely selected along the circumference of the respective double wheel, so that the available installation space can be optimally used or the dimensions of the actuating unit can be reduced. This means that the axes of rotation C, C' do not have to be parallel to the central axis A of the double wheels 18, 18' or to the longitudinal axis B of the instrument, but can theoretically be arranged in any orientation and even independently of each other on the double wheels. However, the Fig. 2 and 3 The arrangement examples shown may be preferred for design reasons: Both the arrangement of the motors 17, 17' parallel to the rotation axis D next to each other according to Fig. 2 as well as by the arrangement of the motors 17, 17' parallel to the longitudinal axis B according Fig. 3 The overall height is reduced. However, it is also conceivable that one of the drive units consisting of the motor and worm shaft is offset by 180° with respect to the double gears 18, 18', so that the motor-worm shaft arrangements are diametrically offset and point in opposite directions, particularly in the arrangement of the motors 17, 17' parallel to the longitudinal axis B, since this does not increase the overall height.

[0046] The structure and operation of the steering gear 13 with regard to the control of the swash plate 14 which can be actuated via the drive units and its bearing are described below with reference to Fig. 4 and 5 described, where in Fig. 4 the worm gear is omitted and only the bevel gears with the bevel gear rings 15, 15' of the double gears are shown.

[0047] Arranged in the shaft 2 of the instrument 1 is a hollow main shaft 21 extending coaxially to the longitudinal axis B of the shaft 2, which is rotatable about the longitudinal axis B of the shaft 2 and extends beyond the proximal end 3 of the shaft 2 into the area of ​​the steering gear 13. The actuating element 8 for actuating the instrument 7 is mounted axially displaceably within this hollow main shaft 21.

[0048] The steering wires 12, which emerge from the shaft 2 at the proximal end 3 of the shaft 2, for which purpose a shaft end piece 3 may be provided at the proximal shaft end, in which through-slots 33 for the steering wires 12 are provided, are fanned out in the examples shown via a fan-shaped disk 22 arranged on the shaft end piece 3 in a rotationally fixed manner with respect to the main shaft 21, whereby the radial distance of the steering wires 12 from the longitudinal axis B of the shaft 2 is increased. While the diameter of the bundle of steering wires 12 coaxially surrounding the longitudinal axis B of the shaft 2 within the shaft 2 or at the distal end 5 in the area of ​​the angulation mechanism 9 is, for example, 4 mm, the diameter of the bundle formed by the steering wires 12 behind the fan-shaped disk 22 is, for example, 18 mm.By increasing the radial distance of the steering wires 12 from the longitudinal axis B of the shaft 2 with the aid of the fan washer 22, not only is the assembly and manufacture of the gear 13 equipped with the swashplate 14 simplified, but the necessary adjustment angle of the swashplate 14 is also proportionally reduced in order to achieve a desired high pivoting angle of the tool tip 6. With the exemplary increase in the diameter of the steering wire bundle from 4 mm inside the shaft 2 to 18 mm behind the fan washer 22, the adjustment angle of the swashplate 14 is correspondingly reduced by 4.5 times compared to the pivoting angle of the tool tip 6 that can be achieved at the distal end. In order to angle this by 90 °, the swashplate 14 only needs to be pivoted by 20 °.

[0049] On the proximal side behind the fan-shaped disk 22, the steering wires 12, which run parallel to the longitudinal axis B of the shaft 2, are fed to the swashplate 14. In an alternative not shown, the steering wires 12 emerging at the proximal end 3 can run directly to the swashplate 14 without a fan-shaped disk, so that the steering wires are fed at an angle to the longitudinal axis B of the swashplate 14. To secure the steering wires 12 to the swashplate 14, through-holes 23 are formed in the swashplate 14 for each steering wire 12. In the example shown, the steering wires 12 are non-positively connected and fixed to the swashplate 14 within the through-holes 23 via grub screws 24. Alternative forms of fastening the steering wires to the swashplate include, for example, welding or crimping or other clamping devices.

[0050] The double wheels 18 and 18' as drive wheels are coupled to the third gear 25, which is preferably designed as a bevel gear and meshes with the two bevel gear rims 15, 15' of the double wheels 18 and 18', so that the rotational axis D of the third gear 25 intersects the common rotational axis A of the double wheels 18 and 18' and the longitudinal axis B of the shaft 2. Through the three meshing gears 18, 18' and 25, every movement of the two double wheels 18 and 18' is transmitted directly to the swash plate 14 coupled to the third gear 25, which causes a direct actuation of the steering wires 12.

[0051] To form a cardanic bearing of the swash plate 14 on the main shaft 21, the swash plate 14 is pivotably mounted on a universal joint disc 28 via two bearing pins 27 arranged offset by 180° to each other, which in turn is pivotably mounted on the main shaft 21 via two bearing pins 29 arranged offset by 180° to each other. Fig. 4 Due to the partial sectional view, only one bearing pin 27 and one bearing pin 29 can be seen.

[0052] The bearing pins 27 of the swash plate 14 and the bearing pins 29 of the universal joint disc 28 are arranged offset by 90° from one another. This bearing allows the swash plate 14 to be pivoted about two axes at right angles to one another relative to the longitudinal axis B of the shaft 2 and to transmit a rotation of the main shaft 21 about the longitudinal axis B to the swash plate 14, whereby the tool tip 6 (cf. Fig. 1 ) can be pivoted in all spatial directions relative to the longitudinal axis B of the shaft 2.

[0053] An alternative cardanic bearing of the swash plate 14 on the main shaft 21 has the Fig. 5 illustrated steering gear 13. This structurally simpler, more compact and easier to assemble bearing arrangement also allows the swash plate 14 to pivot about two degrees of freedom and to rotate about the longitudinal axis B, whereby the tool tip 6 can be pivoted in all spatial directions relative to the longitudinal axis B of the shaft 2 via the steering wires 12 on the distal side. In this case, the main shaft 21 has, in the area provided for supporting the swash plate 14, two guide grooves 20a extending along the main shaft 21 and introduced on both sides or diametrically in the main shaft 21, into which two pins 29 arranged diametrically and radially inwardly pointing on the swash plate 14 engage, wherein Fig. 5 only one guide groove 20a with the pin 29 engaging therein can be seen. As a result of this engagement, the swash plate 14 can be pivoted from a neutral position, in which the swash plate 14 lies in a plane defined by the axis of rotation A perpendicular, i.e. at right angles, to the longitudinal axis B, both about the axis of rotation D and about the axis of rotation A. Superimposed movements by pivoting about both axes of rotation A, D are also possible. Furthermore, the engagement of the pins 29 in the guide grooves 20a allows the transmission of an angle of rotation of the main shaft 21 to the swash plate 14, so that the swash plate 14 can be displaced three-dimensionally relative to the longitudinal axis B of the shaft 2. The maximum tilting or twisting or the maximum tilt and rotation angles about the axes of rotation A and D are determined by the length and depth of the guide grooves 20a in interaction with the inner diameter and thickness of the swash plate 14 and the length of the pins 29.In the example shown, the main shaft 21 has a spherical portion 20b in the area intended for supporting the swash plate 14. The swash plate 14 has guide grooves 20a located thereon, which axially fixes the swash plate 14. The swash plate 14 has a receiving recess contoured to fit the spherical portion 20b.

[0054] As also from Fig. 2 - 5 As can be seen, the spatially adjustable swash plate 14 is mounted in a steering ring 30 which is non-rotatably coupled to the third gear 25. In order to close the toothed chain formed by the double gears 18, 18' and gear 25 into a closed toothed ring which ensures uniform circumferential force distribution, the fourth gear 31 is arranged on the rotational axis D of the third gear 25 opposite the third gear 25, which is also preferably designed as a bevel gear and engages with the bevel gear rings 15, 15' of the two double gears 18 and 18'.

[0055] The swash plate 14 is mounted on a bearing ring 32 (cf. Fig. 4 ) is mounted in the steering ring 30, which is coupled in a rotationally fixed manner to the third gear 25, in order to enable rotation of the swash plate 14 about the longitudinal axis B of the shaft 2. The steering ring 30, which is coupled in a rotationally fixed manner to the third gear 25, is freely rotatable with respect to the fourth gear 31 by means of a bearing ring 42, so that rotation of the fourth gear 31 about its axis of rotation D does not cause any rotation of the steering ring 30 and the swash plate 14.

[0056] The described cardanic mounting of the swash plate 14 on the main shaft 21 enables the swash plate 14 to be displaced three-dimensionally relative to the longitudinal axis B of the shaft 2. If, starting from the Fig. 4 and 5illustrated neutral starting position, in which the swash plate 14 is aligned perpendicular to the longitudinal axis B of the shaft 2, the double wheels 18 and 18' are driven by the motors 17, 17' such that the double wheels 18 and 18' rotate in the same direction, this rotation of the double wheels 18 and 18', due to the meshing engagement with the third gear 25 and the fourth gear 31, causes the structural unit formed from the third gear 25, the swash plate 14 coupled to the third gear 25 via the steering ring 30, and the fourth gear 31 to tilt about the common axis of rotation A of the double wheels 18 and 18'. To simplify the functional description, the alignment of the bearing pins 27, 29 of the cardanic bearing with respect to the axes of rotation A and D is referred to below.In fact, upon rotation of the main shaft 21 and thus of the swash plate 14, the bearing pins 27, 29 are no longer aligned with the axes A and D as shown, so that the pivot axes of the swash plate 14 provided by the bearing pins 27, 29 may deviate from the rotation axes A, D of the steering gear 13.

[0057] In the example of Fig. 4 The bearing pins 27, which are aligned with the rotational axis A of the double wheels 18 and 18' and via which the swash plate 14 is pivotably mounted on the universal joint disc 28, enable this tilting of the swash plate 14 relative to the main shaft 21. This tilting of the swash plate 14 about the rotational axis A relative to the longitudinal axis B of the shaft 2 causes, via the steering wires 12, that the distal side of the tool tip 6 is pivoted in a corresponding manner relative to the longitudinal axis B of the shaft 2. In the example of Fig. 5 the tilting of the swash plate 14 about the axis of rotation A is made possible by the movement of the guide pins 29 in the guide grooves 20a in the ball section 20b of the main shaft 21.

[0058] If, starting from the Fig. 4 and 5 In the neutral starting position shown, in which the swash plate 14 is aligned perpendicular to the longitudinal axis B of the shaft 2, the double wheels 18 and 18' are driven by the motors 17, 17' so that the double wheels 18 and 18' rotate in opposite directions, this rotation of the double wheels 18 and 18', due to the meshing engagement with the third gear 25, causes the structural unit formed from the third gear 25 and the swash plate 14 coupled to the third gear 25 via the steering ring 30 to rotate about the axis of rotation D of the third gear 25.

[0059] In the example of Fig. 4 The bearing pins 29, which are aligned with the rotational axis D of the third gear 25 and via which the universal joint disc 28 is pivotably mounted on the main shaft 21, together with the free rotation of the swash plate 14 relative to the fourth gear 31 due to the steering ring 30, enable this rotation of the universal joint disc 28 relative to the main shaft 21. This rotation of the swash plate 14 about the rotational axis D relative to the longitudinal axis B of the shaft 2 causes, via the steering wires 12, the distal side of the tool tip 6 to be pivoted in a corresponding manner relative to the longitudinal axis B of the shaft 2. Analogously, in the example of Fig. 5 the rotation of the swash plate 14 about the axis of rotation D is effected by the pins 29 engaging in the guide grooves 20a and aligned with the axis of rotation D of the third gear 25.

[0060] Furthermore, it is of course possible to superimpose the described movements so that, for example, the swash plate 14 is tilted about the common axis of rotation A of the double wheels 18, 18' and simultaneously rotated about the axis of rotation D of the third gear 25. By combining the two movement sequences due to the individually controllable motors 17, 17' of the gear 13 and the coupling to the main shaft 21, the swash plate 14 can be adjusted three-dimensionally relative to the longitudinal axis B of the shaft 2, which results in a corresponding spatial displacement of the tool tip 6 due to the coupling via the steering wires 12.

[0061] A surgical instrument 1 designed as described above is characterized in that many thin steering wires 12 can be used to control the pivotable tool tip 6, and this control is carried out sensitively, precisely and reproducibly due to the motorized drive 13 for the swash plate 14 on which the steering wires 12 are mounted.

[0062] An exemplary embodiment of the invention is illustrated in the drawings. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will expediently consider the features individually and combine them into further meaningful combinations. The present invention provides a steering gear 13 for a surgical instrument 1, wherein the steering gear 13 has two motorized drives and is designed to spatially align a swash plate 14 via the setting angles of the two drives. The swash plate 14 is designed to control a distal angulation mechanism 9 of the surgical instrument 1.A first of the two drives comprises a first motor 17, which drives a worm shaft 16, which drives a worm gear ring 19 of a double gear 18 consisting of the worm gear ring 19 and a bevel gear ring 15, and a second of the two drives comprises a second motor 17', which drives a worm shaft 16', which drives a worm gear ring 19' of a double gear 18' consisting of the worm gear ring 19' and a bevel gear ring 15'. The swash plate 14 is arranged between the two bevel gear rings 15, 15', which face each other and lie on a common axis A. Furthermore, a surgical instrument 1 is disclosed, which comprises such a steering gear 13. LIST OF REFERENCE SYMBOLS

[0063] 1Surgical instrument 2Shaft 3Proximal end (shaft) / shaft end piece 4Actuating unit 5Distal end (shaft) 6Tool tip 7Instrument 8Actuating element 9Angling mechanism 11Pivoting link 12Steering wire 13Steering gear 14Swash plate 15, 15'Bevel gear ring of the respective double wheel 18, 18' 16, 16'Worm shaft 17, 17'Motor 18, 18'Double wheel 19, 19'Worm gear ring of the respective double wheel 18, 18' 20a, bGuide groove, ball section 21Main shaft 22Fan washer 23Through holes 24Set screws 25Third gear 27Bearing pins 28Universal joint disc 29Bearing pins 30Steering ring 31Fourth gear 32Bearing ring 33Through slot ACenter axis of the driven double gears 18,18 BLongitudinal axis of the instrument or shaft CDrive axis of the first drive 17 C'Drive axis of the second drive 17' DRotation axis of the third and fourth gear

Claims

1. A steering gear (13) for a surgical instrument (1), wherein the steering gear (13) has two motorised drives and a swash plate (14) and is designed to spatially align the swash plate (14) via the adjustment angles of the two drives, which swash plate is designed to control a distal bending mechanism (9) of the surgical instrument (1), characterised in that a first of the two drives has a first motor (17) which drives a worm shaft (16) which drives a worm wheel rim (19) of a double wheel (18) consisting of the worm wheel rim (19) and a bevel gear rim (15), and a second of the two drives has a second motor (17') which drives a worm shaft (16') which drives a worm wheel rim (19') of a double wheel (18') consisting of the worm wheel rim (19') and a bevel gear rim (15'), and wherein the swash plate (14) is arranged between the two bevel gear rims (15, 15'), which face each other and lie on a common axis (A).

2. The steering gear (13) according to claim 1, characterised in that a drive axis (C) of the first motor (17) is present parallel to a drive axis (C') of the second motor (17').

3. The steering gear (13) according to claim 1 or 2, characterised in that the swash plate (14) is coupled to a third gear wheel (25), which is in engagement with the two bevel gear rims (15, 15') of the two double wheels (18, 18') and whose axis of rotation (D) is at a right angle to the common axis (A) of the driven double wheels (18, 18').

4. The steering gear (13) according to at least one of claims 1 to 3, characterised in that the swash plate (14) is coupled to a fourth gear wheel (31), which is coupled to the two bevel gear rims (15, 15') of the two double wheels (18, 18') and is arranged on the side of the swash plate (14) facing away from the third gear wheel (25).

5. The steering gear (13) according to at least one of claims 1 to 4, characterised in that the worm shaft (16, 16') is a multi-turn worm shaft.

6. The steering gear (13) according to at least one of claims 1 to 5, characterised in that the double wheel (18, 18') is a double wheel (18, 18') manufactured in one piece or consists of a bevel gear and a worm wheel that are connected to each other.

7. A surgical instrument (1) comprising a shaft (2), an actuation unit (4) arranged at the proximal end (3) of the shaft (2) and an instrument (7) arranged at the distal end (5) of the shaft (2) with a tool tip (6) which can be angled by means of a distal bending mechanism (9) and which can be controlled by a swash plate (14) which can be spatially aligned by means of two drives, characterised in that the surgical instrument (1) has a steering gear (13) according to at least one of claims 1 to 6, which has the two drives and is designed to transmit the adjustment angles of the two drives to the spatial orientation of the swash plate (14).

8. The surgical instrument (1) according to claim 7, characterised in that the swash plate (14), for coupling with a third gear wheel (25), which is in engagement with the two bevel gear rims (15, 15') of the two double wheels (18, 18'), is mounted rotatably about the longitudinal axis (B) of the shaft (2) via a bearing ring (32) in a steering ring (30), which is coupled to the third gear wheel (25) in a rotationally-fixed manner, wherein the swash plate (14) is coupled in a cardanic manner to a main shaft (21) running coaxially to a longitudinal axis (B) of the shaft (2).

9. The surgical instrument (1) according to claim 7 or 8, characterised in that the swash plate (14) is pivotably mounted on a universal joint disc (28) via two bearing pins (27) arranged offset by 180° relative to one another, wherein the universal joint disc (28) is pivotably mounted on the main shaft (21) via two bearing pins (29) arranged offset by 180° relative to one another and wherein the bearing pins (27, 29) of the swash plate (14) and the universal joint disc (28) are arranged offset by 90° relative to one another, or the cardanic mounting is provided by two longitudinally extending guide grooves (20a) located diametrically in the main shaft (21) and two pins (29) arranged diametrically and pointing radially inwards on the swash plate (14), wherein each pin (29) engages into one of the guide grooves (20a) such that an angle of rotation of the main shaft (21) can be transmitted to the swash plate (14).

10. The surgical instrument (1) according to at least one of claims 7 to 9, characterised in that steering wires (12) run in the longitudinal direction (B) of the shaft (2) and are connected to the swash plate (14) of the steering gear (13).

11. The surgical instrument (1) according to at least one of claims 7 to 10, characterised in that the fourth gear wheel (31) is coupled to the swash plate (14) via a bearing ring (42) with the steering ring (30), wherein the fourth gear wheel (31) is freely rotatable relative to the third gear wheel (25).

12. The surgical instrument (1) according to at least one of claims 7 to 11, characterised in that an actuating element (8) is mounted so as to be axially displaceable in the shaft (2) and is operatively connected to the actuation unit (4) on the proximal side, and in that the distal bending mechanism (9) of the bendable tool tip (6) consists of swivel members (11) which are arranged at the distal end (5) of the shaft (2) and which are connected to the steering gear (13) via steering wires (12) running in the longitudinal direction of the shaft (2).